As we consider the question of Christian brotherhood, there is an underlying and fundamental question – “Is it a natural human instinct to regard the rest of humankind as brothers and sisters?” There seems in fact to be very little evidence that any sense of brotherhood / sisterhood solidarity for the remainder of the entire human race is indeed a “default” position for us.

We are tribal creatures by instinct (using the word “tribal” in its broadest sense). We feel real kinship with our family, with our “clan”, with those of the same religious faith, with those of our nation and (most dangerously of all) with those of our particular race. There is often overlap between these categories – particularly between religious faith, race and nationhood – and we are happy to reinforce these overlaps with our own irrational prejudices and intolerance. It is certainly difficult to argue that our natural disposition makes us believe that we are brothers and sisters of all humankind, the world.

In one of his early books, The Meaning of Christian Brotherhood, the former Pope Benedict XVI – then Professor Joseph Ratzinger - distinguished between two ideas of brotherhood, closed (for the initiated only) and open (encompassing the world). As he pointed out, the post-Enlightenment secular western world may have believed in the idea of universal brotherhood but it could not achieve it, if anything entirely the contrary.. One of its fruits, the French Revolution, may have made a slogan of fraternité but it was in fact violent confrontation between social and economic classes that was the reality. Marxism, which saw class struggle as the authentic actuality, could only conceive of a resolution of such struggle at the end of time. We must then conclude that any nurturing of a sense of universal brotherhood / sisterhood requires effort rather than sentiment or romanticisation.

For any of us within the Judeo-Christian tradition, there is a crucial starting point within the scriptures - Genesis, with its powerful affirmation that, as human persons created by God, we are each made in His image and likeness. I am grateful to friends within the Orthodox traditions of the Church for making this absolutely central to my own faith. Too easily in the Western traditions we can gloss over this vital and fundamental truth of our essential being and the being of others. But it is sometimes a real task to see others in God’s image. As Rabbi Jonathan Sacks has put it so clearly, it is indeed difficult to see the image of God in those who are not in our image.

Seeking, with God’s grace, to see a divine image in every other person is a task for us all, for those of other faiths beyond the Jewish and Christian faiths. For those of no religious faith, the thinking non-believer, there is an equivalent challenge to see some parallel of the divine image in every other human person, and many non-religious humanists accept this challenge.

But what does it mean in real terms to treat all others as brothers and sisters? In my own human experience (as part of a small family with only one sibling, a brother five years older than I am) coupled with what I hope is religious understanding, I would briefly suggest three facets to brotherhood/sisterhood.

The first is that we give to the other person the dignity of an absolute equality with us. No other human person is less loved, or more loved, by God than are we. Good parents do not have favourites. Good parents never - to use an idiom that may not translate well - play one child off against another. We are the children, not simply of good human parents, but of the God of an absolute righteousness. As children of God - equal in his sight and equally loved by him – there is no greater dignity attaching to any one individual than there is to any other child of God.

Secondly, a good brother or sister will allow his or her siblings “space” to be themselves. Because we are made in God’s image does not mean that we are intended to be identical. It takes real maturity and also generosity of spirit to allow others the dignity of being something very different from us and yet cherished by us for what they are, even that very difference from us. In a human family, we expect such generosity. How can we not extend this to brothers and sisters under God whose culture, race or faith is not identical to ours?

Thirdly (and of particular importance), a characteristic of any good brother or sister is that they will want the very best for their siblings. Regardless of temperamental differences, or difference in tastes, interests or perspectives on life, a brother or sister will always want - more than anything else - the good of their sibling. In illness, distress, loneliness, bereavement or need of any other kind, the brother or sister can be relied on to give loving help, comfort and support.

If we see these as features of human family relationships that are not dysfunctional, how can we not see them as the essential characteristics of being God’s children, and hence being brothers and sisters together in his love?

In a specifically Christian setting, I always believe that within the context of worship and liturgy, it is insufficient to say, “My brothers and sisters..”. We should always say, “My brothers and sisters in Christ..”, because this is the basis and foundation of our brotherhood and sisterhood. It is not a simple human affinity or kinship, but it is deeper and richer because its underpinning is the love of God in Christ for each one of us, equally.

Broadening it out, we believers should surely seek to say to all other persons, “Brothers and sisters in God’s image”? And should non-believers who actually care about what it is to be a human person not find a way of saying, “Brothers and sisters in a sacred image that is beyond mere primal human functioning”?

If we could grasp our brotherhood and sisterhood with all humankind, how could we ever want anything other than the good and the dignity of every other human person, and true peace for them, whoever, whatever and wherever they may be? This, surely, would be nothing less than the unity of the world.